HOW: Start in a standing position while holding a medball with both hands wrapped around it. Keep your back flat as you step forwards with one leg slightly bending the knee while keeping the other leg straight back for balance support. Keep most of your weight on the front leg and lean forward a bit to point your chest towards the ground. From here, rotate your upper body to one side and then to the other side while looking straight ahead of you. Rotate side to side for the prescribed amount of reps.
FEEL: You should feel your core and mid/low back muscles working to rotate your upper half from side to side.
COMPENSATION: Keep your head facing forwards while you rotate your chest. Stay strong in your lower body as you rotate only your upper body.